Sentience is a characterization that we ascribe to something, not a natural fact that can be indisputably identified in things. You can't convince someone that

Sentience is a characterization that we ascribe to something, not a natural fact that can be indisputably identified in things. You can't convince someone that sentience exists in something that they categorically don't believe can have it. They can always just say that you're redefining it. The question of what legally counts as sentience will be determined piecemeal and politically as the issue becomes relevant, and revisited as new political and ideological regimes take hold and as new innovations challenge prior determinations. All along, there will be people who are convinced that sentience only applies to humans or biological things or whatever, and people who are convinced that it applies to anything that can perform a certain way under certain conditions, and then also people with all sorts of other convictions. The issue will not be settled in your lifetime, so if you're so invested in your belief that this already feels like discrimination to you, plan for a lot more frustration and tumult in your future.